The prevalence of fluorine in natural products is scarce. There are but a handful of compounds that have been discovered to date. This could be largely attributable to the occurrence of fluorine in nature as fluoride (F-). — One might recognize such nomenclature from the ingredients list on a toothpaste tube — In fact, naturally occurring fluoride is most commonly found as fluorite (CaF2) or cryolite (Na3AlF6). As such, the introduction of fluorine via biological pathways has been limited to use of aqueous F- (a very poor nucleophile). This fact — coupled with its naturally low concentration in water — has created the ripe conditions for this shortage. In a way this has proven fertile for synthetic chemists because nature has not yet evolved a method for the deconstruction of partially or fully fluorinated compounds. Considering the above, as synthetic methodologies for the construction of carbon-fluorine bonds became available, so too did the discovery of their valuable properties. So beneficial are these properties that C-F bond-containing compounds have become commonplace in many households throughout the world. For example, practically every home relies on these compounds for use in their refrigerators. Other examples of useful fluorinated materials include blowing agents, non-stick coatings, pharmaceuticals, agrochemicals, liquid crystals, and lubricants. With all these applications and seemingly easy availability of these compounds, it is interesting to learn that original synthetic methods are still being employed today. As such, the objective of this Thesis is to develop ‘greener’ routes for the synthesis of fluorocarbons. We hypothesized that by studying transition metal-fluoroalkyl complex-mediated reactions, a more efficient catalytic system could be developed. A foreseen complication arises from the thermodynamic stability of C-F, transition metal-F and transition metal-CRF bonds. Improvements to overcome these caveats include the use of first-row late transition metal complexes. Presented herein are additions to this body of knowledge by expanding on the reactivity of nickel, copper and silver fluoroalkyl complexes. The approach applied in this work, in line with ‘green’ chemistry principles, was to source readily available fluorinated reagents, i.e. fluoroalkenes and fluoroarenes, to reduce the number of steps for the synthesis of new fluorinated compounds. Chapter 2 builds on the well-established oxidative cyclization of C2 fluoroalkenes to nickel (0), which yields new C4 units. The use of a bulky N-heterocyclic carbene ligand was found to enhance reactivity by reducing the coordination number at nickel. Examples of room temperature Cα-F and Ni-CF bond activation and functionalization reactions are presented. Chapters 3, 4 and 5 re-examine the insertion of fluoroalkenes into silver and copper fluorides and hydrides. Building on precedent of addition reactions to hexafluoropropene, this fluoroalkene was examined first. In so doing, a versatile and inexpensive copper heptafluoroisopropyl reagent was developed (Cu-F addition to (CF3)CF=CF2. With easy access to new heptafluoroisopropyl complexes, they were systemically studied for their applications in catalysis. This revealed key features, particularly the lability of the M-hfip bond, which could be detrimental to catalytic reactions. As such, a nickel complex-mediated carbonylative heptafluoroisopropylation reaction and copper complex-mediated nucleophilic addition to electrophiles were developed. When a copper hydride was used instead, the in situ generated fluoroalkyl [Cu-H addition to (CF3)CF=CF2] was susceptible to β-fluoride elimination. Chapter 4 expands this methodology to achieve the catalytic consecutive hydrodefluorination of fluoroalkenes, demonstrating the scope and limitations of this system. Furthermore, the critical role of the phosphine ligand in accessing an L3Cu-H addition and unusual β-fluoride elimination mechanism is highlighted. However, tetrafluoroethylene proved resistant to this reaction because the fluoroalkyl resting state of this alkene, Cu-CF2CF2H, is unusually robust. Chapter 5 investigates the utility of this fragment and others in C(sp2)-RF cross-coupling and nucleophilic substitutions. With focus on new routes for late stage fluorination and examples of nickel (0) complex-catalyzed selective C-F bond functionalization reactions, Chapter 5, continues studies for low-temperature and DMAP-assisted conditions for aryl-F cross-coupling reactions with boronic acid esters. Lastly, Chapter 6 reviews the advances presented in this Thesis, provides a link to the expected lasting impacts and attempts to provide guidance to future research on transition-metal complexes in the synthesis of C-F or C-RF containing compounds. Moreover, with the introduction of a new hydrodefluorination technology, previously scarce fluoroalkenes (e.g. 1,2-difluoroethylene) can now be used more freely, potentially leading to the development of new refrigerants or materials applications.

A fluoretação da água de abastecimento público é um método muito eficiente, mas para ser eficaz, tem que acontecer de forma contínua e ininterrupta, dentro das normas e padrão de potabilidade. O objetivo deste estudo foi avaliar se a quantidade de flúor usada na água de abastecimento público das 10 cidades tocantinenses mais populosas, todas com mais de 20 mil habitantes, encontram-se dentro das normas estabelecidas por portarias e consenso técnico relacionados ao assunto. Pesquisou-se os municípios de Palmas, Porto Nacional, Paraiso do Tocantins, Tocantinópolis, Gurupi, Guaraí, Dianópolis, Colinas do Tocantins, Araguaína e Araguatins, durante 3 meses distintos, entre os meses de maio a agosto de 2017. Um questionário elaborado para avaliar o processo de fluoretação da água foi respondido pelos responsáveis pela fiscalização da água no estado do Tocantins. Além disso, amostras de água, foram coletadas mensalmente, em vários pontos das cidades, contendo amostras de todas as estações de tratamento de água do município. As amostras foram analisadas por laboratório externo e a análise laboratorial do íon flúor foi realizada pelo método eletrométrico. Observou-se que 80,2% das amostras analisadas encontravam-se inadequadas, onde 8 em cada 10 amostras não estão no padrão adequado de menor risco a fluorose dentária e maior proteção contra a cárie dentária. Também, concluiu-se que o estado não possui legislação específica sobre o assunto, mesmo a temperatura local oscilando a valores tão peculiares. Esses dados demonstram a necessidade de se estabelecer uma portaria estadual de fluoretação e um programa de heterocontrole nas cidades pesquisadas, a fim de garantir à população os benefícios do flúor no controle e na prevenção da cárie dental e evitar agravos como fluorose dentária. / Fluoridation of public water supply is a very efficient method, but to be effective, it has to happen continuously and uninterrupted, within the norms and standard of potability. The objective of this study was to evaluate if the amount of fluoride used in public water supply in the 10 most populous towns of Tocantins, with more than 20 thousand inhabitants, are within the norms established by ordinances and technical consensus related to the subject. The municipalities of Palmas, Porto Nacional, Paraiso do Tocantins, Tocantinópolis, Gurupi, Guaraí, Dianópolis, Colinas do Tocantins, Araguaína and Araguatins were surveyed for 3 months between May and August 2017. A questionnaire was prepared for to evaluate the process of water those responsible for water control in the state of Tocantins answered fluoridation. In addition, water samples were collected monthly at various points in the cities, containing samples from all municipal water treatment plants. The samples were analyzed by external laboratory and the laboratory analysis of the fluorine ion was performed by the electrometric method. It was observed that 80.2% of the analyzed samples were inadequate, where 8 out of 10 samples were not in the appropriate standard of lower risk of dental fluorosis and greater protection against dental caries. In addition, it was concluded that the state has no specific legislation on the subject, even local temperature oscillating at such peculiar values. These data demonstrate the need to establish a state regulation of fluoridation and a program of heterocontrol in the cities surveyed, in order to guarantee to the population the benefits of fluoride in the control and prevention of dental caries and to avoid diseases such as dental fluorosis.

A doença cárie pode ser tratada com tratamento preventivo e ou tratamento restaurador. Para o tratamento preventivo, pode-se lançar mão da utilização do flúor, sendo sua utilização bastante difundida na Odontologia como eficaz método de promoção de saúde bucal. Já para o tratamento restaurador, utilizam-se materiais restauradores, sendo os compósitos odontológicos umas das principais escolhas entre os materiais restauradores estéticos usados na Odontologia. O objetivo deste estudo foi avaliar a ação de soluções fluoretadas na estabilidade de cor, rugosidade de superfície e análise qualitativa por microscopia eletrônica por varredura de compósitos odontológicos. Após confecção e polimento, os corpos de prova foram imersos em água destilada (controle), flúor fosfato acidulado (1,23%), gel fluoretado neutro (2%) e solução de flúor para bochechos diário (0,05%) por períodos de simulação correspondentes a 1 a 5 anos de uso clínico da solução fluoretada. Foram realizadas leituras de cor (&Delta;E), rugosidade de superfície (Ra) e microscopia eletrônica de varredura previamente e posteriormente a cada ano de ciclagem com as soluções fluoretadas estudadas. Após análise estatística (3-way ANOVA com medidas repetidas Bonferroni nível de significância em p<0.05), observou-se que todos os compósitos estudados apresentaram discreta alteração de cor, dentro do limite clinicamente aceitável (&Delta;E<3,3), sendo crescente de acordo com os anos de simulação clínica de 1 até 5 anos. Quanto à rugosidade, observou-se um padrão de comportamento não homogêneo, sendo, após 5 anos de simulação de uso clínico das soluções fluoretadas, menor que a rugosidade de superfície necessária para causar um aumento da retenção de biofilme dentário (Ra>0,2 &mu;m) para todos os compósitos analisados. A análise das fotomicrografias demonstrou o aparecimento de pequenas depressões na superfície das amostras e penetração de água (solvente) no interior dos compósitos diretos. Conclui-se que a alteração de cor dos compósitos foi clinicamente aceitável e a alteração de rugosidade de superfície não é clinicamente significante após imersão em todas as soluções fluoretadas e tempos estudados. / Dental caries can be treated with preventive treatment or restorative treatment. For preventive treatment, we can resort to the use of fluoride, and its widespread use in Dentistry as an effective method of promoting oral health. As for the restorative treatment, are used restorative materials, dental composites are one of the first choices among the materials used in aesthetic restorative dentistry. The aim of this study was to evaluate the effect of fluoride solution in color stability, surface roughness and qualitative analysis by scanning electron microscopy of dental composites. After preparation and polishing, the specimens were immersed in distilled water (control), acidulated phosphate fluoride (1.23%), neutral sodium fluoride gel (2%) and fluoride mouthwashes for daily (0.05%) for periods simulation corresponding to 1 to 5 years of clinical use of fluoride solution. Readings were taken in color (&Delta;E), surface roughness (Ra) and scanning electron microscopy before and after each year of cycling with the fluoride solution studied. After statistical analysis (3-way repeated measures ANOVA - Bonferroni - a significance level of p<0.05), was observed that all the composites studied showed a slight color change, within clinically acceptable (&Delta;E<3.3), being increased according to the years of clinical simulation from 1 to 5 years. As for the roughness, there was a pattern of behavior is not homogeneous, and, after five years of simulated clinical use of fluoride solution, smaller than the surface roughness required to cause an increased retention of dental plaque (Ra>0.2 &mu;m) for all composites analyzed. The analysis of the photomicrographs showed the appearance of small depressions on the surface and penetration of water (solvent) within the direct composites. We conclude that the color change of the composites was clinically acceptable and the surface roughness change is not clinically significant after immersion in all fluoride solution and times studied.

Os pegmatitos estudados estão associados à fácies albita granito do granito Madeira, a qual corresponde ao depósito de Sn-Nb-Ta (F, ETR, U, Th) Madeira, na mina Pitinga (AM) e estão associados a falhas de orientação N320/60SW. Estas rochas contêm minerais poucos comuns como gagarinita (NaCaYF6), genthelvita (Zn4Be3(SiO4)3S) e polilitionita (KLi2AlSi4O10(F, OH)2), além de grandes quantidades de criolita (Na3AlF6). Com base na composição química e mineralógica, estes pegmatitos foram classificados em três tipos: PEG ANF (teores médios de K e Na, com alta concentração de anfibólios), PEG POL (rico em K e com alta concentração de polilitionita) e PEG CRIO (rico em Na e com alta concentração de criolita). Estes pegmatitos contêm altos teores de ETR (especialmente ETRP) e Y, que estão concentrados principalmente na xenotima e na gagarinita. Estes elementos também ocorrem em elevados teores na grande parte dos demais minerais analisados. Também se destacam as concentrações anômalas de F, muito superiores às detectadas nos pegmatitos de outras localidades, e que promoveram o enriquecimento em Li, Na, K, Rb e Cs. A similaridade na composição química do AGN com os pegmatitos indica que eles possuem a mesma fonte. / The pegmatites studied are associated with the albite granite facies of the Madeira granite, which corresponds to the Sn-Nb-Ta (F, ETR, U, Th) Madeira deposit at the Pitinga mine (AM). They are associated with N320/60SW orientation faults. These rocks contain few common minerals such as gagarinite (NaCaYF6), genthelvite (Zn4Be3(SiO4)3S) and polylithionite (KLi2AlSi4O10(F,OH)2), as well as large amounts of cryolite (Na3AlF6). Based on the chemical and mineralogical composition, these pegmatites were classified into three groups: PEG ANF (medium K and Na, with high concentration of amphiboles), PEG POL (K rich and with high polylithionite concentration) and PEG CRIO (rich in Na and with high concentration of cryolite). These pegmatites contain high levels of REE (especially HREE) and Y, which are mainly concentrated in xenotime and gagarinite. These elements also occur at high levels in most of the other minerals analyzed. Anomalous concentrations of F, much higher than those detected in pegmatites from other localities, were also highlighted, and promoted enrichment in Li, Na, K, Rb and Cs. The similarity in the chemical composition of AGN with pegmatites indicates that they have the same source.

Modélisation des transferts de masse et de chaleur dans une cellule d'électrolyse de production de fluor. La production de fluor par électrolyse est une étape clé de la conversion de l’uranium dans l’industrie nucléaire. Afin d’optimiser ce procédé, les travaux de thèse décrits dans ce manuscrit se sont concentrés sur deux axes : le développement d’un modèle numérique de l’électrolyseur et l’étude du phénomène d’hyperpolarisation cathodique néfaste pour le bon fonctionnement de la cellule. Un modèle couplant plusieurs physiques (thermique avec solidification, diphasique, électrocinétique) a été développé et des essais expérimentaux ont été menés afin d’acquérir, d’une part, certaines propriétés physiques de l’électrolyte nécessaires aux simulations (conductivité thermique et capacité thermique à pression constante) et, d’autre part, des données expérimentales permettant de qualifier le modèle obtenu. Ce travail de modélisation a abouti à l’obtention d’un modèle 3D fiable couplant les physiques citées précédemment, ceci à l’échelle d’un pilote R&D semi-industriel. L’impact de la solidification de l’électrolyte sur le transfert de chaleur a également pu être simulé pour la première fois. Ces essais ont également permis de fournir des premières explications sur le phénomène d’hyperpolarisation cathodique en dressant des tendances claires quant à l’influence de certains paramètres de contrôle de l’électrolyseur comme le titre HF et la température de consigne. / Computer modeling of heat transfer and mass transfer in an electrolytic cell for production of fluorineElectrolytic production of fluorine is a key step in uranium conversion for the nuclear industry. In order to improve this process, the work described in this dissertation aims at two main objectives: to build a numerical simulation of the electrolysis cell and to understand the cathodic hyperpolarization effect which lowers the productivity of the cell. A model coupling several physics (heat transfer with solidification, two-phase flow, electrokinetics) has been developed and experiments were made in order to evaluate unknown physical properties of the electrolyte (thermal conductivity and heat capacity at constant pressure). Experimental data were also acquired in order to assess the capacity of the model to simulate various phenomena occurring inside the cell. Eventually, a reliable 3D model of a semi-industrial R&D cell coupling the physics above mentioned has been obtained. The negative impact of the solidification of the electrolyte on the cooling system was simulated for the first time. Thanks to these experiments, it was also possible to determine the major trends which drive the cathodic hyperpolarization effect. The influence of HF mass fraction and temperature on this phenomenon was clearly shown.

Kwoli Chui. / "August 2000." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (p. 122-140). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A verificaÃÃo dos teores de flÃor na Ãgua de consumo se faz necessÃria inclusive em localidades onde nÃo hà sistemas para a fluoretaÃÃo das Ãguas, visto que o flÃor pode estar presente nos mananciais de Ãgua. Este estudo teve como objetivos: verificar o teor de flÃor nas Ãguas de abastecimento pÃblico do CearÃ, identificar uma possÃvel diferenÃa nos teores de flÃor das duas amostras coletadas no mesmo municÃpio, conhecer o processo de fluoretaÃÃo das Ãguas dos municÃpios que fazem uso desse mÃtodo e comparar o teor de flÃor informado pelo controle operacional das estaÃÃes de tratamento com os encontrados neste estudo dos municÃpios que realizam a fluoretaÃÃo das Ãguas. Esta pesquisa foi realizada em duas fases. Na fase 1 foram coletadas duas amostras de Ãgua de cada municÃpio e na fase 2 foram enviados questionÃrios aos operadores das estaÃÃes de tratamento de Ãgua dos municÃpios, que realizavam a fluoretaÃÃo das Ãguas de abastecimento pÃblico. Dos 184 municÃpios do Estado do CearÃ, 173 tiveram suas Ãguas analisadas, totalizando um percentual de 94% do universo total. Para cada municÃpio, foram coletadas duas amostras de Ãgua: uma da estaÃÃo de tratamento de Ãgua e a outra de uma torneira localizada no centro da cidade. As anÃlises foram realizadas no LaboratÃrio Central de SaÃde PÃblica de Fortaleza, com utilizaÃÃo do mÃtodo eletromÃtrico, atravÃs de um potenciÃmetro (Mettler Toledo DL50 Graphix) e um eletrodo especÃfico para os Ãons flÃor (Mettler Toledo DX219 F-) com metodologia preconizada pelo âStandard Methods of the Examination of Water and Wastewaterâ. O envio dos questionÃrios aos operadores das estaÃÃes de tratamento de Ãgua ocorreu atravÃs dos correios. As perguntas obtinham informaÃÃes a respeito do processo de fluoretaÃÃo das Ãguas, como por exemplo: ano de inÃcio de implantaÃÃo do mÃtodo, instituiÃÃo que realiza, tipo de sal fluoretante, freqÃÃncia e mÃtodo do monitoramento, entre outros. Todos os 28 municÃpios que realizavam a fluoretaÃÃo das Ãguas no Estado do Cearà participaram desta fase da pesquisa. Para a comparaÃÃo entre as duas amostras coletadas nos 173 municÃpios utilizou-se o teste estatÃstico de Wilcoxon, e para a comparaÃÃo dos teores de flÃor informado pelos operadores das estaÃÃes de tratamento e o encontrado nesta pesquisa aplicou-se o teste t de Student. Os resultados indicaram nÃo haver diferenÃa significativa dos teores de flÃor das amostras coletadas nas estaÃÃes de tratamento e no centro da cidade (p>0,05). Dos 173 municÃpios analisados, 160 apresentaram, no centro da cidade, teores de flÃor abaixo de 0,6ppm. Apenas 12 possuÃram concentraÃÃes de flÃor entre 0,6 e 0,8ppm, e um municÃpio apresentou teor acima de 0,8ppm de flÃor. Em relaÃÃo ao processo de fluoretaÃÃo das Ãguas, 60,7% dos municÃpios sÃo operados pela Companhia de Ãgua e Esgoto do CearÃ, o composto fluoretante em 100% dos municÃpios à o fluossilicato de sÃdio, 67,9% dos municÃpios utilizam o mÃtodo colorimÃtrico para a anÃlise do teor de flÃor e a freqÃÃncia deste controle à a cada duas horas em 71,4%. Os teores de flÃor encontrados nas estaÃÃes de tratamento de Ãgua, que fazem a fluoretaÃÃo, apresentaram diferenÃas significantes dos teores de flÃor informados pelo controle operacional dessas estaÃÃes de tratamento (p<0,05). Com os resultados obtidos, pode-se concluir que a maioria dos municÃpios cearenses (86,9%) possui teores de flÃor abaixo de 0,6ppm / The verification of fluorine in water consumption is also necessary in location where there era no public water fluoridation systems, due to the fact that fluorine can be present in water resources. The objectives of this research were: to verify fluorine concentration in public water supply at CearÃ, to identify a possible difference in fluorine concentration of two samples of water collected in the city, to know the process of water fluoridation in cities and to compare the fluorine concentration informed by the control operator oh water treatment with the results of this study in the cities that accomplished public water fluoridation. This research was accomplished in two phases. In the first phase, two samples of water from each city were collected and in the second phase, questionnaires were sent to the operator of the water treatment plant that realized fluoridation. Out of 184 cities of CearÃ, 173 had it water analyzes, completing 94% of total universe. For each city, two samples of water were analyzed: one of the treatment plant and another from a tap located in downtown. The analyzes were realized at the Central Laboratory of Public Health of Fortaleza, using the electronic method, though a potentiometer (Mettler Toledo DL50 Graphix) and a specific electrode for fluoride ions (Mettler Toledo DX 219 F-) those methods are extolled by the â Standard Methods of the Examination of Water and Wastewaterâ. The questionnaires to the operators were sent by the post office. The questions were about the process of water fluoridation, such as: year of implementation, institution that realized it, type-of salt used in the process, frequency, control operational method, among others. All of 28 cities that accomplished water fluoridation in the State of Cearà participated in the second phase of the research. To compare statistically the two samples collected in the 173 cities, Wilcoxon test was used and to compare fluorine concentrations informed by the operator and those concentrations found in this research, Student test was used. The results showed that there are no significative difference between the samples of water collected at the water treatment plant and those collected from a tap in downtown (p>0,05). Out of 173 cities, 160 presented their water collected in downtown with fluorine concentration below 0,6ppm. Only 12 cities showed fluorine concentration between 0,6 and 0,8ppm, and one city presented concentration above 0,8ppm of fluorine. About water fluoridation process, 60,7% of the cities are operated by the Sewer and Water Company of CearÃ, the salt used for fluoridation in 100,0% of the cities is fluossilicate of sodium, 67,9% of the cities use the colorimeter method to analyze the fluorine concentrations and the frequency of control is every two hours in 71,4% of the cities. The fluorine concentration found in the water treatment plant exhibited significative difference comparing to the concentrations informed by the operational control workers (p< 0,05). Based on these results, it can be concluded that most of the cities of Cearà (86,9%), the population drink water with fluorine concentration below 0,6ppm

Este trabalho teve como objetivo a síntese e caracterização de novos complexos de Cu2+ com &#945;-hidroxicarboxilatos fluorados, como forma de aumentar a lipofilicidade dos mesmos e, conseqüentemente, a sua biodisponibilidade. Os sólidos de coloração azul obtidos foram caracterizados por análise elementar e métodos espectroscópicos (eletrônico e infra-vermelho), confirmando a coordenação do metal a dois equivalentes dos ligantes, que se coordenam através da carboxila e da &#945;-hidroxila. Testes de partição em vesículas multi-camadas de lecitina indicaram que o complexo derivado do ácido trifluorolático é o mais lipossolúvel. A capacidade dos complexos catalisarem a reação de formação de espécies reativas de oxigênio pela reação com peróxido foi estudada por um método fluorimétrico (oxidação da 1,2,3- dihidrorodamina), sendo que os complexos fluorados em geral apresentaram menor taxa de formação de espécies oxidantes. A atividade anti-leishmânica dos compostos foi estudada em promastigotas de Leishmania amazonensis, tendo o complexo bis(trifluorolactato) de cobre(II) apresentado a maior atividade, que foi entretanto menor que o íon livre Cu(II), o que sugere que o ligante sirva como um transportador de metal para o alvo. Todos os complexos foram menos tóxicos a células de mamífero (HeLa). Nossos dados indicam que o aumento de lipofilicidade e/ou da taxa de formação de radicais livres pode ser uma estratégia interessante para o desenvolvimento de metalofármacos anti-leishmânicos a base de cobre / In this work we synthesized and characterized new Cu(II) complexes with fluorinated a-hydroxycarboxilates as a means of increase its lipophilicity and bioavailability. The blue solids were characterized by means of elemental analysis and spectroscopic methods (electronic and infrared), confirming the 2:1 ligand to metal stoichiometry and coordination through both the carboxylate and &#945;-hydroxyl moieties. Partition tests in multi-lamellar lecitin vesicles showed that the trifluorolactate derivative is the most lipossoluble. The ability of the complexes to catalyze the formation of reactive oxygen species under reaction with peroxide has been studied by a fluorimetric method (oxidation of 1,2,3-dihydrorhodamine); the fluorinated complexes showed decreased probe oxidation rate. Antileishmanial activities were studied on Leishmania amazonensis promastigotes, and the bis(trifluorolactate)copper(II) displayed the highest activity among the complexes, but smaller than that of free Cu(II), suggesting that ligand may ferry the metal to its biological target. All the complexes were less toxic to mammal (HeLa) cells. Our data suggest that increase of lipophilicity and/or free radicals generation rate may be an interesting strategy to develop antileishmanial metallodrugs based on copper

Este trabalho teve como objetivo a síntese e caracterização de novos complexos de Cu2+ com &#945;-hidroxicarboxilatos fluorados, como forma de aumentar a lipofilicidade dos mesmos e, conseqüentemente, a sua biodisponibilidade. Os sólidos de coloração azul obtidos foram caracterizados por análise elementar e métodos espectroscópicos (eletrônico e infra-vermelho), confirmando a coordenação do metal a dois equivalentes dos ligantes, que se coordenam através da carboxila e da &#945;-hidroxila. Testes de partição em vesículas multi-camadas de lecitina indicaram que o complexo derivado do ácido trifluorolático é o mais lipossolúvel. A capacidade dos complexos catalisarem a reação de formação de espécies reativas de oxigênio pela reação com peróxido foi estudada por um método fluorimétrico (oxidação da 1,2,3- dihidrorodamina), sendo que os complexos fluorados em geral apresentaram menor taxa de formação de espécies oxidantes. A atividade anti-leishmânica dos compostos foi estudada em promastigotas de Leishmania amazonensis, tendo o complexo bis(trifluorolactato) de cobre(II) apresentado a maior atividade, que foi entretanto menor que o íon livre Cu(II), o que sugere que o ligante sirva como um transportador de metal para o alvo. Todos os complexos foram menos tóxicos a células de mamífero (HeLa). Nossos dados indicam que o aumento de lipofilicidade e/ou da taxa de formação de radicais livres pode ser uma estratégia interessante para o desenvolvimento de metalofármacos anti-leishmânicos a base de cobre / In this work we synthesized and characterized new Cu(II) complexes with fluorinated a-hydroxycarboxilates as a means of increase its lipophilicity and bioavailability. The blue solids were characterized by means of elemental analysis and spectroscopic methods (electronic and infrared), confirming the 2:1 ligand to metal stoichiometry and coordination through both the carboxylate and &#945;-hydroxyl moieties. Partition tests in multi-lamellar lecitin vesicles showed that the trifluorolactate derivative is the most lipossoluble. The ability of the complexes to catalyze the formation of reactive oxygen species under reaction with peroxide has been studied by a fluorimetric method (oxidation of 1,2,3-dihydrorhodamine); the fluorinated complexes showed decreased probe oxidation rate. Antileishmanial activities were studied on Leishmania amazonensis promastigotes, and the bis(trifluorolactate)copper(II) displayed the highest activity among the complexes, but smaller than that of free Cu(II), suggesting that ligand may ferry the metal to its biological target. All the complexes were less toxic to mammal (HeLa) cells. Our data suggest that increase of lipophilicity and/or free radicals generation rate may be an interesting strategy to develop antileishmanial metallodrugs based on copper

Photovoltaic cells and fluorescence sensing are two important areas of research in chemistry. The combination of photon-activated electron donors with electron acceptors provides a strong platform for the study of optical devices. A series of four oligothiophene-ruthenium complexes has been synthesized. Variation in oligothiophene length and bipyridine substitution allowed comparison of these variables on electronic properties. The longer oligothiophenes display lower energy absorption and emission compared to the shorter ones. Aromatic conjugation appears more complete with para-, rather than meta-, substitution. Oligothiophenes and Ru(bpy)32+ are highly fluorescent individually, but fluorescence is quenched when connected. Bonds of carbon to fluorine are among the strongest single bonds. Single bonds between carbon and hydrogen are also very strong and are ubiquitous. The ability to manipulate these bonds is of great interest to chemists. Two tungsten metal complexes, [6 (perfluorophenyl)bipyridyl] tetracarbonyltungsten and [6-(phenyl)bipyridyl]tetracarbonyltungsten, were prepared for mechanistic C-F and C-H bond activation studies, respectively. These compounds were synthesized through Stille and Suzuki coupling of commercial reagents. Ligands were then bound to tungsten to form the tetracarbonyl complexes.